The present invention relates to proppants and methods of making proppants. The present invention further relates to the use of proppants for hydrocarbon recovery. The present invention further relates to the method of fracking a well using the proppants of the present invention.
Proppants are materials pumped into oil or gas wells at extreme pressure in a carrier solution (typically brine) during the hydrofracturing process. Once the pumping-induced pressure is removed, proppants “prop” open fractures in the rock formation and thus preclude the fracture from closing. As a result, the amount of formation surface area exposed to the well bore is increased, enhancing recovery rates.
Ceramic proppants are widely used as propping agents to maintain permeability in oil and gas formations. High strength ceramic proppants have been used in the hydrofracture of subterranean earth in order to improve production of natural gas and/or oil. For wells that are drilled 10,000 feet or deeper into the earth, the proppant beads need to withstand 10 kpsi or higher pressure to be effective to prop the fracture generated by the hydrofracture process. Currently only proppants formed from high strength materials, such as sintered bauxite and alumina have sufficient compressive and flexural strength for use in deep wells. These conventional high strength materials are expensive, however, because of a limited supply of raw materials, a high requirement for purity, and the complex nature of the manufacturing process. In addition, such high strength materials have high specific gravity, in excess of 3.0, which is highly undesirable for proppant applications. Producing high strength proppants with low specific gravity is also a challenge. In field applications, the transportability of proppants in wells is hindered by the difference of specific gravities of proppant and carrying fluid. While light weight oxide materials, such as cordierite, have low specific gravity, they have a relatively weak flexural strength and stiffness.